Portable motor vehicle cabin air purifier

ABSTRACT

A portable air purifier for reducing pollutants in the passenger cabin of a vehicle to concentrations at least as low as the US-EPA National Ambient Air Quality Standards for: carbon monoxide, ozone, nitrogen dioxide, sulfur dioxide, lead, and particulate matter; plus benzene to a European ambient air standard. The purifier includes an air inlet and air outlet in communication with the vehicle cabin, with air circulation provided by a DC electric motor/blower attachable to a vehicle power plug. The filter assembly includes a specified series of filter media packets and a HEPA filter. The machine&#39;s preferred location is in the center of a rear seat where it can serve as an armrest/console and be secured by a seat belt.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of Provisional Application Ser. No.60/188,009 filed in the United States Patent and Trademark Office onMar. 9, 2000, and which addresses the same subject matter.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the purification of air, particularly in thepassenger cabins of motor vehicles, but also in hospitals, nursinghomes, other health care environments, and industrial environments, andespecially to the use of a plurality of packed bed filter media packetsand a HEPA filter placed in a predetermined sequence within a portableair purifier that can be placed as a console/arm rest at selectedlocations within a motor vehicle cabin, or by some adaptation in avehicle trunk or bed of a pickup truck, or placed in any of such otherenvironments, and in the case of a vehicle the air purifier operatesindependently of the vehicle ventilation system.

2. Description of the Prior Art

The literature in the field of Indoor Air Quality (IAQ) may use the term“ambient air” to refer to the air within an indoor room, while in thecontext of air quality generally the term often refers to “outside air.”For clarity, the term “ambient air” is used herein in the latter sense,and the air within the motor vehicle cabin that is to be purified isreferred to as “cabin air,” although that cabin air will of course becontinually supplied with “outside” or “ambient” air by virtue of thevehicle ventilation system, open windows, or the like. Morespecifically, “ambient air” herein means that air through which thevehicle is being driven.

Considerable effort has been directed toward reducing air pollutioninside the cabin of motor vehicles. With hundreds of different kinds ofair pollutants around and inside motor vehicles traveling on congestedhighways, this is no easy task. Most of this effort has targeted dust,pollen, and some odors. Vehicle manufacturers in Europe, Japan and theUSA now offer air filtration subsystems for the passenger cabins of someof their new automobiles. These subsystems are typically placed withinthe ventilation system of new cars and serve as gross particulatefilters. Some of these subsystems also have small amounts of activatedcarbon to reduce odors. These ventilation subsystems are intended tocapture particles that are 3 to 8 microns in diameter and larger, butthey are not designed to reduce substantially the extensive fine (2.5micron in diameter and smaller) particulate matter over any extendedperiod of time.

Some of the particulate filters now being installed in the ventilationsystems of new cars use electrostatic non-woven filter media. Theelectric charges on these media help to capture fine particulate matter;however, as the filter media fills, the charge and thus theeffectiveness of such media are diminished. The majority of particles bynumber that appear in the cabin air environment in fact fall within thesize range of less than one micron in diameter. These submicronparticles are not effectively reduced by current ventilation subsystemdesigns, but yet they present the greatest health hazard to human beingssince they penetrate deeply into the respiratory tract. Also, placementof filters that contain activated carbon within ventilation system doescapture some gases, but with no specific standard of effectiveness forindividual gases, the object seemingly being simply that of reducing“odors” for purposes of customer satisfaction, but with little or nothought being given to the reduction of any identified pollutants. Onemajor limitation inherent in such systems also is that they have beendesigned to minimize pressure drop in order to maintain a strong flow ofair, for purposes of heating or cooling, but as a result any actual fineparticle purification of the air being circulated becomes minimal.

Some inventors have proposed stand-alone cabin air filter systems thatare to be permanently mounted in the trunk, the rear window deck, or theceiling (head liner) of automobiles. Again, most of these proposedsystems are designed as gross particulate filters, with small amounts ofactivated carbon added to reduce smoke and generic odors. These, too,have had little or no capacity to rapidly filter and re-circulate cabinair. Some of these devices are small electronic air cleaners that targetfine particulate matter, but also have the potential for generatingozone, itself a pollutant. Such devices also require frequent cleaningto prevent arcing and to minimize ozone production.

In most cases, the stand-alone devices of the prior art have hadinsufficient air flow to reduce substantially the continuing flow ofpollutants that comes into the vehicle cabin through the ventilationsystem, and through leakage around doors and windows. No deviceheretofore proposed is portable, re-circulates cabin air at effectiverates of cubic meters per minute (m³/min) or the corresponding cubicfeet per minute (CFM), and employs a specific sequence of filters thathas been especially designed to remove specific pollutants, includingfine particulate matter, lead, carbon monoxide, ozone, sulfur dioxide,nitrogen dioxide, benzene and other hydrocarbons. A number of thefilters used in the invention are of the packed bed type, which type hasa long history with respect to purifying air in buildings, but to theinventor's knowledge, there have been no successful attempts to adaptthe packed bed technology to cabin air purification. Also, no prior artdevice intended for vehicle cabin air purification that is known to thisinventor has targeted the specific air pollutants for which the EPA orother agencies have established ambient air quality standards, with thegoal of reducing the concentration levels of those pollutants at leastto below the defined health standards. This seems to have resulted (a)from not being aware until the last several years of the high levels ofpollutants that are actually found in a vehicle cabin while drivingthrough crowded urban streets; and (b) from emphasizing in research whatparticular vehicle manufacturers were doing about cabin air pollutionrather than on what needed to be done if those high levels of pollutionwere to be reduced. Perhaps most significantly, the inventor is aware ofno prior test data, such as those reported herein, in which an airpurifier was installed in a vehicle that was then driven through thestreets, while collecting air quality measurements both with thepurifier operating and with it not operating, so that by comparison ofthose data a practical measurement of the efficacy of the purifier couldbe established.

Particular patents known to the inventor that relate to airpurification, especially in the cabins of motor vehicles, will now bedescribed. U.S. Pat. No. 3,722,182 issued Mar. 27, 1973 to Gilbertsontouches on the use of an air filtering device mounted on the rear windowdeck of an automobile and functions independently of the heater/airconditioner/air intake (plenum) system of the vehicle. (An alternativeembodiment that connects directly to the air intake of the vehicle isalso described.) For removal of particulate matter, the device employselectrostatic plates, although in the more recent state of the art it isknown that HEPA filters better serve that purpose, and do not requirethe frequent cleaning or replacement that is necessary for electrostaticsystems.

U.S. Pat. No. 3,883,637 issued May 13, 1975 to Benedict describes anactivated charcoal filter element having dispersed mixtures of copperand chromium oxides, chromates, dichromates and the like for purposes orremoval of H₂S and catalytically, similar air-borne sulfur compoundssuch as mercaptans, organic sulfides, thiophene compounds, thioethersand organic sulfoxides.

U.S. Pat. No. 3,870,495 issued Mar. 11, 1975 to Dixson, et al.,describes the use of non woven fibers of wood, paper, hemp and the liketo avoid having periodic gaps in the material as is characteristic ofwoven fabrics. Secondly, the filters are used in multi-layer orlaminated form so as to block any gaps that might occur by way ofmanufacturing imperfections with respect to particular pieces of fabric.

U.S. Pat. No. 4,207,291 issued Jun. 10, 1980 to Byrd et al. describesthe use of a fabric substrate impregnated with MnO₂ for the removal ofozone from the air in aircraft cabins.

U.S. Pat. No. 4,610,703 issued Sep. 9, 1986 to Kowalzyk describes asingle filter installed within a vehicle heater/cooling system.

U.S. Pat. No. 4,629,482 issued Dec. 16, 1986 to Davis describes aportable air purifier for use in rooms (as opposed to vehicle cabins)that employs a HEPA filter for particulate removal and operates on ACpower. The need to replace the filters after long use is shown to theuser externally by the appearance of a pulsation in the air flow rate.At an initial stage with a clean filter, operation occurred at ameasured air flow rate of 350 cubic feet per minute (CFM).

U.S. Pat. No. 4,658,707 issued Apr. 21, 1987 to Hawkins et al. describesan air purifier for vehicle interiors, disposed principally within theheadliner, that includes a fan and smoke filters, together with a smokedetector that automatically initiates operation of the device upon thedetection of smoke.

U.S. Pat. No. 4,722,747 issued Feb. 2, 1988 to Armbruster describes anair filter system to be mounted by bolts beneath the roof of a vehicleand including a pair of blowers dispersed at opposite ends of the devicefor blowing out air, an air intake opening in the middle, and both foamand activated charcoal filters interposed there between.

U.S. Pat. No. 4,917,862 issued Apr. 17, 1990 to Kraw et al. describes afilter system for the removal of mercury, bacteria, pathogens and othervapors, especially with respect to mercury vapors in a dental office. Asequence of filters includes a fibrous pre-filter, then a filter havinga honeycomb structure or the like, within which a plurality of cells arepartially filled with activated carbon pellets, and then preferably apost-filter. The quantity of pellets introduced may lie between 30% and90% of the total cell volume, whereby the pellets are “swirled” in theair stream passing through the filter, this motion of the adsorbentpellets being intended to increase adsorbent-adsorbate contact.Operation of the device at air flow rates of at least 700 CFM is said tobe preferred, although operation at rates up to 1200 CFM is also noted.

U.S. Pat. No. 5,004,487 issued Apr. 2, 1991 to Kowalzyk describes an airfilter assembly for use in passenger compartments of motor vehicles thatis installed within the vehicle heating/cooling system and is airpressure driven to clean the air coming into the vehicle. A sensorprovides warning when the filter needs cleaning or replacement.

U.S. Pat. No. 5,192,346 issued Mar. 9, 1993 to the same inventor(Kowalzyk) employs a pleated flat filter to permit greater air flow.

U.S. Pat. No. 5,042,997 issued Aug. 27, 1991 to Rhodes describes anenvironmental control system for a building which includes an air filterthat has a series of particulate filters and a chemical and activatedcharcoal filter.

U.S. Pat. No. 5,221,292 issued Jun. 22, 1993 to Aoyams describes an aircleaning system for vehicle passenger compartments which includes twoair cleaners: a single air cleaner for cleaning passenger compartmentair when the pollution level is low; and a second cleaner for conditionsof high pollution within the vehicle is drawing in and cleaning outsideair, while the first cleaner discharges compartment air to the outside.

U.S. Pat. No. 5,683,478 issued Nov. 4, 1997 to Anonychuk describes anair filter device featuring a bottom base unit having a hollowcylindrical filter unit to be housed within an existing blower motorassembly under the hood of a car.

U.S. Pat. No. 5,879,423 issued Mar. 9, 1999 to Luka et al. describes afilter system having a filter body in the form of a plate-like filterelement exemplified by an “active carbon mat” disposed between at leasttwo planar frame parts, wherein two such frame parts enclose the filterelement and are then held together by snaps, the structure furtherpermitting construction of an array of such filter elements in series,and the system as a whole being intended to be part of the airconditioning system of the vehicle.

Some effort has been made to provide air purification, or at least someattention to vehicle cabin air quality, in add-on or after-marketdevices. For example, the web sitehttp://www.realgoods.com/shop/shop.1.cfm?dp=107&ts=1053857 operated byReal Goods offers a three-stage auto air filter that employs activatedcarbon, an electret charged medium, and a Zeolite VOC (“Volatile OrganicCompounds”) filter, but the efficacy of the device is not known, otherthan claiming to recycle the cabin air in about six minutes. The sitehttp://www.realgoods.com/shop/shop.1.cfm?dp=107&ts=1053856 from the samecompany offers an auto ionizer to help precipitate air pollutants, butnothing is said about either air circulation or tested effectiveness.(Both sites visited Dec. 17, 2000.)

Some technical literature has also addressed cabin air purification, forexample, in the article by Heinz H. Bitterman entitled “History andWorld Wide Trends in Cabin Air Filter Testing,” published inFluid/Particle Separation Journal, Vol. 3, No. 2, August 2000, pp.152-155. This article points out the air test standards currently beingemployed in Europe, which are then compared to the less stringent U.S.standards. (The article notes, for example, that General Motors vehiclesfor the European market will have filtration for both particles andodors, whereas the American versions of such vehicles will only haveparticle filters.) The article also remarks that “if it could be managedto provide filters being effective with diesel soot, a major step torecognizable air quality improvement inside cars would be made,” butonly the use of activated carbon as a filter material, and not the HEPAfilter, which the present data indicates is necessary (to remove thefine particulates onto which many of the other pollutants appear toadhere), is proposed to reach that goal. Bitterman also provides noexperimental data collected from moving vehicles, as are the dataprovided herein.

An article by Tadeusz Jaroszczyk et al. entitled “Filtration Performanceof High Efficiency Cabin Filters for Operators' Protection in DustyEnvironments,” published in Fluid/Particle Separation Journal, Vol. 3,No. 2, August 2000, pp. 156-164 (Jaroszczyk I), discusses the cabin airfiltration systems of mobile mining equipment with respect to theefficacy of particular filter types, and also both recirculating and airintake ventilation systems. The article discusses minimum air flow rates(e.g., 43 m³/hr=25.3 CFM), a “nominal” air flow rate of 100 m³/h beingused in the reported laboratory tests, filter pressure drops (e.g., 20Pa), and “dust capacity,” a parameter for use in high dust environments.

An article by Tadeusz Jaroszczyk et al. entitled “Media Needs forAutomotive Cabin Air Treatment” published in Proceedings, Filtration '94Conference, American Filtration and Separations Society, pp. 123-147(Jaroszczyk II), sets out criteria that filter media should meet inorder to be used in cabin air filtration. Particular stress is given tothe constraints that are present in ventilation system filter design, inlight of the (presumed) limited space available for such filtration, aswell as a perceived need to maintain a high air velocity for purposes ofheating, ventilation and air conditioning (HVAC), with the resultantshort residence time of the air within the filter system being said toreduce filter effectiveness. The article indicates, e.g., (p. 125), that“conventional high efficiency filters operate at low filtrationvelocities and excessively large spaces would be required to accommodatethese filters in a car,” and(p. 126) that “current ventilation systemdesigns do not allow for the incorporation of conventional highefficiency filters (HEPA) typically required if ‘lung damaging’particles have to be removed.”

The proposed solution, but for which no specific means are given, isnoted (p. 130) as follows: “An independent car ventilation system withrecirculating air flow should be used to control contaminants frominternal sources. Filters in this system can be installed in the trunk,under the roof (in the headliner), or under the seats. Since there ismore space in these locations, such filters can be larger thanventilation system filters. A low flow velocity in these filters can bemaintained so that high filter and adsorber efficiency can be achieved.”The article also discusses odor reduction and the air velocity valuesused in laboratory tests, indicating (pp. 145-146) that with respect toodor control, “under the flow conditions common in this application,adsorbent media did not have sufficient efficiency and life to removechallenge substances.”

An article by Ogaki et al., “The Road Test of Car Cabin Filters inJapan,” Fluid/Particle Separation Journal (American Filtration andSeparation Society), Vol. 11, No. 1, April, 1998 (pp. 101-106) describesthe testing of a number of filter types, including a two-layer dustremoval type having a prefilter mainly composed of polyester fiber and abinder, and a micro fiber layer composed of melt-blown polypropylene. Afour-layer type combines that dust removal type with another two layersintended to remove odors, comprising a layer of activated carbongranules disposed on a polyester backing layer. The article also setsout the Japanese Environmental Standard for suspended particulate matter(SPM) (which was said to be satisfied nowhere in Tokyo) and reportsroadside measurements made by the Japanese Environment Agency for sulfurdioxide, nitrogen dioxide and hydrocarbons, as well as efficiency datafor the various filters derived in this study, but no attempt is made torelate this efficiency study to the achievement of any environmentalstandard. Road tests of odor perception and dust concentration were alsotaken, and showed a clear correlation between odor perception and peaksin measured dust concentrations, the observance of these beingattributed to vehicle exhaust gas.

An article by Samuel E. Lee, et al. of the Ford Motor Company entitled“Odor Filter Design Process,” Fluid/Particle Separation Journal(American Filtration and Separation Society), V. 9 No. 3, October 1996,pp. 185-190, addresses cabin air filtration in terms of (1) theconstraints (high air flow, low pressure drop, small package size)placed on any system that will be incorporated into a vehicle HVACsystem and (2) customer perception of odors, without reference to anydirected attempt to attain positive health benefits or the meeting ofair quality standards. The article also states that “in most cases, theodor filter is intended as a customer comfort feature rather than ahealth and safety feature,” and further that the filter design processis to depend significantly on “what the customer wants,” which in turnis to be based on market research. Some laboratory comparisons of filterperformance, at face velocities of approximately 0.75 m/sec and 340m³/hr flow rates, are also reported.

This industry emphasis on low pressure drops and customer comfort isprobably best shown in a practice noted in the article by Olaf Kievit,“Cabin Air Filter Loading Under Real-Life Conditions,” Advances inFiltration and Separation Technology (American Filtration and SeparationSociety), V.11, 1997, pp. 188-192, wherein the end of a filter's “usefullife” is defined as that point at which the pressure drop exceeds 1000Pa, which as to one test occurred after only 30 hours. The issueaddressed by the present invention is not that of any such pressuredrop, but rather the question of whether the filter is still able toreduce cabin air pollution levels to below government standards, underambient air conditions in which those levels far exceed such standardswhen the invention is not in use. (It is shown by the present inventionthat the industry concern for low pressure drops may be misplaced—an airpurifier external to the HVAC system of a vehicle can not only beprovided, but can be provided so as to add further utilitarian andindeed aesthetic value to the vehicle. Placement of the air purifierexternal to the vehicle HVAC system eliminates that pressure drop as amajor issue of concern.)

The web site http://www.epa.gov/ttn/amtic/pmspec.html, under the heading“A final draft copy of the “Particulate Matter (PM2.5) SpeciationGuidance Document,” at pp. 24-31 (pp. 15-22 as printed), describes indetail the general characteristics of PM_(2.5) particles, identifies the“target species” for which speciation of the chemical components in testanalyses of air is sought by the U.S. Environmental Protection Agency,and in particular identifies a very wide range of pollutants in thisPM_(2.5) category, and their sources, that become a part of our everyday air. (Site visited Dec. 17, 2000.)

To emphasize further the social importance of this issue, more recentresearch has shown that the concentration level of major air pollutantsin the passenger cabins of vehicles operating on congested highways istypically 1.5 to 10 times higher than the level found at nearbymonitoring stations. The data in the following Table I (wherein MTBE ismethyl-tertiary butyl ether, MQL means “below quantification limit,”i.e. not detectable, and “LAS-X” is a type of optical particle counter)were reported by the California Environmental Protection Agency AirResources Board as Release 99-18 on Jun. 10, 1999, as an ExecutiveSummary entitled “Measuring Concentrations of Selected Air PollutantsInside California Vehicles,” of a research study that included datacollection in both Los Angeles and Sacramento (only the Los Angeles dataare shown here).

TABLE I Los Angeles Los Angeles Pollutant In-Vehicle Ambient MTBE, μg/m³20 to 90 10 to 26 Benzene, μg/m³ 10 to 22 3 to 7 Toluene, μg/m³ 22 to 5410 to 40 PM_(2.5), μg/m³  29 to 107* 32 to 64 PM₁₀, μg/m³  29 to 107* 54 to 103 Formaldehyde, μg/m³ <MQL to 22     <7 to 19   Carbon Monoxide3 to 6 <MQL Black carbon, μg/m³  3 to 40 na LAS-X, tot. particles/cm³2,200 to 4,600 na [*Added note: Because of the identity of these twoentries, it is suspected that one of them is a typographical error,given that the PM₁₀ measurement necessarily includes measurement ofparticles 2.5 μm or less, and these values could be the same only if theair contained no particles larger than 2.5 μm. (Most likely the figurefor PM₁₀ is in error, since the PM₁₀ values found in the present testswhen the apparatus comprising invention was not in use # weresubstantially higher than those of Table I, and in any case PM₁₀ valuesare generally about twice PM_(2.5) values.)]

Because the levels found at road-side monitoring stations in many majorcities now exceed in themselves the health standards established by theU.S. EPA, the much higher levels of those same pollutants insidevehicles can present an even more significant health risk to passengers.

This same problem exists worldwide, and is rapidly getting worse. Asjust one example of that, the article “Urban Air Quality ManagementStrategy in Asia—Jakarta Report (World Bank Technical Paper No. 379,1997), Jitetendra J. Shah and Tanvi Nagpal, Eds. pp. 1-2, has expressedthe following in an Executive Summary to the report:

Larger and more diverse cities are a sign of Asia's increasingly dynamiceconomies. Yet this growth has come at a cost. Swelling urbanpopulations and increased concentration of industry and automobiletraffic in and around cities has resulted in severe air pollution . . ..

Jakarta's population doubled between 1981 and 1991 . . . . In 1995, themetropolitan area's population was 11.5 million. This growth wasaccompanied by a tremendous rise in the number of vehicles on Jakarta'sroads from approximately 900,000 to 1,700,000 . . . .

These developments are reflected in the city's deteriorated air quality.Pollutant concentrations near the main roads and in the northern part ofthe urban area are sometimes extremely high. The highest values havebeen measured in the northern part of Jakarta, but many stations seem tobe influenced by local sources. The bus terminals in Pulo Gadung andCililitan both show average total suspended particles (TSP) values above300 μg/m³. Overall, traffic and industries are the main sources of airpollution in Jakarta. Total TSP emissions in Jakarta are estimated at96,733 tons/year. Particulate matter of 10 microns or less (PM₁₀)emissions total 41,369 tons/year, and nitrogen oxide (NO_(x)) emissionsare estimated at 43,031 tons/year. TSP concentrations are lower in theoutskirts, averaging 100-150 μg/m³. The annual TSP averages in the mostpolluted areas are 5-6 times the national air quality guideline.Resuspension from roads, diesel and gasoline vehicle emissions, anddomestic wood and refuse burning are the main sources of particulatepollution. Drivers, roadside residents, and those who live near largesources are most severely affected.

High ozone concentrations, measured 30 to 40 kilometers outside Jakarta,indicate that secondary pollutants have developed as a result of NOx andVOC emissions in Jakarta . . . .

While attaching an economic value to morbidity and mortality stemmingfrom air pollution can be difficult, there is anecdotal as well asestimated evidence to suggest that the health of Jakarta's residents isunder assault. Dose response equations used for valuing health impactsreveal that PM₁₀ caused a total of 4,364 excess deaths, 32 millionrestricted activity days (RAD), 101 million respiratory symptom days(RSD), innumerable emergency room visits, asthma attacks, cases ofbronchitis in children, and hospital admissions, at a total cost ofabout US $300,000 (based on Indonesian data) in 1990.”

Those health risks will of course include the possible spread andinhalation of airborne infectious agents, particularly in the case ofvehicles that accept transient passengers as part of their dailyfunction, such as police cars, limousines, taxicabs and ambulances. Thefollowing Table II contains a listing of some well known such infectiousagent, indicating both the scientific name of the agent and theparticular infection(s) that each may cause, and were selected from JoanLuckmann and Karen Creason Sorensen, Medical-Surgical Nursing: APsychophysiological Approach (W. B. Saunders Company, Philadelphia,1987), 3d Ed., pp. 120-121.

TABLE II List of airborne infectious agents: Infections: Corynebacteriumdiphtheriae Diphtheria Staphylococcus aureus Wounds, pneumonia,cellulitis, dermatitis, food poisoning, septicemia Streptococcuspneumoniae Lobar pneumonia, eye infections, meningitis, peritonitisHaemophilus influenzae Pneumonitis, pneumonia, meningitis N eisseriameningitidis Meningitis, pneumonia Mycobacterium tuberculosisTuberculosis Cryptococcus neoformans Pneumonia, meningitis Aspergillusspecies Aspergillosis Hepatitis B Serum hepatitis Herpes zoster Chickenpox (primary) Shingles (recurrent) Rubella Rubella and rubella syndromein newborns exposed prenatally Enteroviruses Poliomyelitis, asepticmeningitis Myxoviruses Influenza

Such airborne pathogens are to be found in nursing homes and hospitalsor the like as well, and as will be noted below, a portable embodimentof the invention equally finds application in that context.

With the exception of certain special purpose applications, such as theKraw et al. patent that is principally concerned with mercury in dentaloffices, or the Benedict patent which treats only sulfur compounds (onlyone of which, sulfur dioxide, ranks as a major criteria air pollutant),and in spite of the EPA documentation of this pressing need for“speciation” of the offending materials, the prior art discloses littleattempt to address the issue of motor vehicle cabin air pollution interms of specific chemical elements or compounds, notably those that areknow to be toxic, and/or for which standards for air purity have beendefined.

The foregoing literature may be summarized by saying that efforts in theair purification industry, except perhaps in the mining environment andin industrial and office environments under the requirements of OSHA,have primarily emphasized customer satisfaction rather than health.Secondly, to establish minimum flow rates as standards (e.g., asmentioned in Jaroszczyk I, noted above) would appear at least to requiremore precise definition. If the flow rate is increased by increasing theair velocity rather than the filter cross section, the residence time ofany particular segment of a gas will decrease and by that assumption thefilter “efficiency” will decrease accordingly, as noted in JaroszczykII. Cited studies of filter efficiency also seem to be directed moretowards demonstrating the greater efficiency of some particularcompany's product rather than contributing to any understanding of theproblem, since one cannot draw any general conclusions from comparisonsof studies that in one case use air velocities of 5 cm/sec (JaroszczykII, cited above) while another uses air velocities of 0.75 m/sec (Lee,cited above).

Even reported efficiency values are difficult to interpret. That is, theAmerican Society of Heating, Refrigerating, and Air ConditioningEngineers, Inc. (“ASHRAE”) defines one efficiency test method, while anewer penetration test by the “DOP” (dioctyl phthalate) method, DOPpenetration being essentially the converse of the ASHRAE efficiency, mayalso be cited, and comparable values of these results are given in TableIII below as set out by Hollingsworth & Vose Company (undated salesbrochure) for a selection of that company's products:

TABLE III Grade # ASHREA Efficiency % DOP Pen. HE-1113 90-95 35 HF-055380-85 46 HF-0513 80-85 48 HF-0612 80-85 50 HF-0493 60-65 88 HF-062260-65 86

Using comparable methods, and taking this terminology at face value, anefficiency of 90-95% should mean a penetration rate of 5-10%, hence thefigures just cited do not provide an adequate guide to filterperformance except in purely relative terms.

In light of the foregoing, this inventor accordingly sought to developand create an air purification device for use in vehicle cabins andelsewhere that would reduce the concentration levels of EPA—criteriapollutants therein to an amount at least less than the National AmbientAir Quality Standard (NAAQS) for each pollutant, as set by the EPA interms of concentration levels above which the pollutant is presumed tocreate a health risk to human beings. The EPA had initially establisheda NAAQS for hydrocarbons, but that standard was subsequently abandonedin favor of a new category of air pollutants under the title “Toxics.”Many hydrocarbons, including benzene, are toxic; benzene is indeed aClass A carcinogen, i.e. a proven human cancer causing agent. A studypublished by the South Coast Air Quality District in Californiadetermined that among all the air toxics measured inside the cabins ofoperating motor vehicles, benzene presented the greatest health risk forcommuters in the Los Angeles basin. Therefore, it is an especiallytargeted pollutant for this invention.

Table IV below shows the pertinent NAAQS, the more stringent standardsset by the State of California, or in the case of benzene, a standardset by The Netherlands for application in Europe (neither the EPA norCalifornia appear presently to have an ambient air standard for benzene.Indeed at this time, as best known to the inventor, the EPA has set noambient air standards for any toxics.)

(In Table IV, “μg/m³” means “micrograms per cubic meter, “ppm” means“parts per million, “ppb” means “parts per billion,” “PM 10” means aparticle size of 10 micrometers or less in diameter, “PM 2.5” means aparticle size of 2.5 micrometers or less in diameter, and the timeperiods on the right in the right hand column mean that measuredconcentration values averaged over the stated time periods should notexceed the standard shown in the middle column. These standards are setout in greater detail in FIG. 27.)

TABLE IV Concentration Air Pollutant Level Standard Government Benzene10 μg/m³ The Netherlands, annual Carbon Monoxide 20 ppm California, onehour Ozone 100 ppb (0.10 ppm) California, one hour Nitrogen Dioxide 250ppb (0.25 ppm) California, one hour Sulfur Dioxide 636 ppb (0.636 ppm)EPA, 24 hour Lead 1.5 μg/m³ EPA, quarter Particulate Matter: PM 10 150μg/m³ EPA, 24 hour PM 2.5 65 μg/m³ EPA, 24 hour

Experimental Background

With respect to vehicle ventilation systems in general, in theexperimental data to be discussed below, which indicate a reduction ofair pollution to below defined standards when an embodiment of thepresent invention was in operation but pollution values in excess of thestandards when that device was not in operation, measurements were madein a vehicle that had a filter system built in to its ventilation systemand in most cases was in operation, but was not effective since themeasured pollution levels when the embodiment of the invention thenbeing used was not turned on still exceeded those standards.

Thus to this inventor, the prior art disclosed no systematic treatmentof air purification technology that was at all adapted for applicationin vehicle cabins, but only the partial solutions as previouslydescribed. Suggestions as to what might ideally be done were notprovided in any structural detail, evidently in light of the muchgreater emphasis on minimal “customer satisfaction” as a tool inmarketing, and thus an unwillingness to invest in the development oftruly effective filter systems. The data presented herein and elsewhereestablish a long felt need, but one that is presently unmet. Thus, afterexperimenting with a variety of filter media, blowers and filter devicedesigns and packaging, it occurred to the inventor that the sequence offilters could be as significant a factor as the type. Also, thestructure of the filters ultimately employed by the inventor was made tocombine two filtering processes, i.e., the “packaging” for one filtermedium was provided by another material that would itself contribute asignificant filtering effect. A 7 m³/min (250 CFM) prototype of theinvention having the desired filter sequence was then built and tested.Selected filter media packets were fabricated as hereinafter describedand installed in the device, and their effectiveness was tested in thefield in the Portland, Oreg. area. That same device was also tested inthe Los Angeles area in August of 1999, when pollution was high. Thatprototype appears herein as the embodiment installed in the vehicletrunk as shown in FIG. 8.

Two smaller versions of that prototype were then constructed, one stillwith a 7 m³/min (250 CFM) rated blower, and the other with a 5 m³/min(176 CFM) blower. These two prototypes, that are described as theportable embodiment herein, were field tested in Los Angeles, Portland,and Bangkok, Thailand. Exemplary results of these tests are describedand shown below with reference to corresponding figures. Additionaltests not shown here were also carried out, the results of which wereuniformly consistent with those reported here.

SUMMARY OF THE INVENTION

The invention provides air purification apparatus that reducessubstantially the amount of specific major air pollutants found insidemotor vehicle passenger cabins or similar environments, thus to providea lessening of human health risk and increased comfort for passengers inmotor vehicles or persons in those other environments. In a motorvehicle, the apparatus is not added to the existing ventilation system,but has its own blower, which preferably operates at variable speed on12 volts direct current. A preferred embodiment of the apparatus isportable and can be installed in any vehicle, operating through powerfrom a cigarette lighter outlet or similar power source, or it can bewired directly into the vehicle's electrical system. In particular, in amulti-vehicle family, the air purifier is easily moved from one vehicleto another. The air purifier is of light weight, a preferred embodimentof which is adapted to be placed in the center of the rear seat where itcan be secured by a seat belt, and can be used as a console and armrest, with pouches thereon to hold personal articles, including theusual holders for small change, audio tapes and CDs, and also cupholders. If not desired for use as an arm rest or console, the devicecan be secured in any vacant seat location. Alternatively, the apparatuscan be strapped to the floor, especially of a van or SUV (sport utilityvehicle), or mounted in the trunk of a car using special ducting to drawair from the passenger cabin into the apparatus and thence from theapparatus back into the vehicle cabin.

A principal object of the invention is to maintain vehicle cabin airthat is free of harmful levels of the respirable particles (fineparticulate 2.5 microns and smaller in diameter size), noxious and/ortoxic gases, and airborne infectious agents, which present substantialhuman health risk. The apparatus is not so limited in size or power thatit has the severe pressure drop restrictions common to filters placed inthe ventilation systems of vehicles. It substantially reduces specificincoming exhaust-related pollutants, as well as passenger-generatedpollutants such as tobacco smoke, viruses and bacteria. The apparatusalso has the substantial benefit of being able to filter andcontinuously re-filter air in the cabin, rather than have the filteroperate on a one-pass basis as occurs within many ventilation systemdesigns. The apparatus operates independently from, and will notadversely affect, any existing vehicle ventilation system.

Another object of the invention is to provide an air purifier devicethat operates as a high capacity linear air-flow system. The apparatusdraws in cabin air through a large grate at a first end of an airtighthousing, and then passes that air through an air conduit that contains 3to 5 individually fabricated and aligned filter media packets thatcontain in a pre-determined sequence at least gross particulate media(i.e., some fine particulate material may also be captured), desiccants,adsorbents, chemisorbents, and catalysts, as well as a deep pleated HEPAparticulate filter and a post-filter. (Except where the contextindicates otherwise, the term “sorbent” is used hereafter so as toencompass both adsorption and absorption). A 5 m³/min (176 CFM)—7 m³/min(250 CFM) rated 12 volt DC blower pulls the air through that airconduit. The resulting air is then expelled through an outlet at the topof the purifier housing, which outlet may preferably be of about 7.6 cm.(3 inch) diameter. Wiring includes a switch to vary the blower speed,installed in series on an electrical cord that connects the air purifierwith the cigarette lighter outlet in the vehicle or a similar powersource. If portability of the device is not sought to be retained, thewiring can be connected directly to the vehicle electrical system. Theblower is preferably shock mounted, using gaskets on either side of themotor mounting plate to reduce noise and provide air seals.

Yet another object of the invention is the reduction of cabin airpollutants to meet EPA, State of California, and European Ambient AirQuality Standards. That object is found to be accomplished through theuse of a uniquely designed sequence of filter media packets that wasespecially conceived for this device. The preferred sequencing of filtermedia packets as shown below has been identified through repetitivetesting, although the sequence can be modified to treat a less demandingpollutant mix targeted in certain geographical areas during particularseasons of the year:

1. Desiccant-sorbent packet containing various types of silica gel,zeolite and/or molecular sieves, within an at least gross particulatemedium envelope.

2. Sorbent packet containing various types of packed activated carbongranules or pellets, within an at least gross particulate mediumenvelope. (The term “carbon particle” is used hereinafter to encompassboth pelletized and granular carbon, and also any other particulateforms of carbon as may be known to a person of ordinary skill in theart.)

3. Catalyst packet to break down carbon monoxide, within an at leastgross particulate medium envelope. To function properly the catalystpacket must be preceded in the air-flow stream by desiccants to reducemoisture and by sorbents to capture sulfur and other acids which couldpoison the catalyst and make it inoperative.

4. Sorbent packet containing various types of coconut based activatedcarbon granules, beads, and/or powder, within an at least grossparticulate medium envelope.

5. HEPA pleated filter (tested to remove 99.97% of particles measuring0.3 microns in diameter, and more efficient for both smaller and largerparticles), about 7.6 cm. (3 inches) deep.

6. A second filter of the type indicated in 4 above, or a coconut-basedcarbon impregnated fiber medium, to capture any residual gases andodors.

The use of the above filtering means in the indicated sequence willdecrease passenger cabin air pollutants across a broad spectrum, andmeet the specific health standards for ambient air shown above in TableI. In particular, the effective reduction of diesel exhaust fumes, whichgenerally comprise fine particulate matter to which a variety of toxicand/or noxious substances are adhered, require both the sorbent filtermedia and the HEPA filter. The use of adsorbents and chemisorbents willfilter out nitrogen oxides including nitrogen dioxide, sulfur oxidesincluding sulfur dioxide, and many harmful hydrocarbons, especiallyincluding aromatic hydrocarbons such as benzene and toluene. The HEPAfilter, which is essential for capturing and holding PM_(2.5) andsmaller (the fine respirable) particles, will remove a wide range ofpollutants, including the following:

a) heavy metals such as lead, cadmium, mercury and asbestos;

b) noxious gases that attach to tiny particles such as sulfate andnitrate precipitants from gasoline and diesel engines and coal firedutility plants;

c) disease-causing microorganisms, including both bacteria and viruses,as well as fungi.

The foregoing objectives are met by the present invention by providingthe following features:

1. a uniquely effective and long-lasting filter sequence for removal offine particles and specific gases inside vehicle cabins to meetgovernment health standards for ambient air;

2. accomplishment of the above goal with a portable, stand-alone airpurifier that can be installed in existing vehicles as an after-marketadd-on rather than being built into the ventilation system of new cars;

3. location of the purifier in a convenient and safe place inside thecabin, particularly in the center of the rear seat, so it also can serveas an armrest or console. This placement allows enough space for thedevice to be fitted with a powerful motor and many different filtermedia, hence the air circulation is sufficient to accomplish thefiltration goal; and

4. alternative location of the purifier in the vehicle trunk, withducted air fluidly connected to the vehicle cabin, a structure thatisolates the blower from the vehicle passengers while still providingeffective air purification and a convenient console.

Proper and most efficacious use of the apparatus (hereinafter designatedas an air purifier) as well as adequate evaluation of its utility,requires an understanding of what are the relevant data, along withactual measurements of air purity. Reference in the prior art as to thenumber of times within so many minutes that the air within someparticular volume is exchanged, even though that parameter is widelyused as a marketing tool, provides no information whatever about thereduction of air pollution within a vehicle, given that such parametercould as well be used to describe the performance of a simple fan. Thesame is true of air flow rate standards, since the air flow rate issimply another way of expressing the rate of air exchange within a givenvolume. It is not some purported “efficiency” of a filter that issought, but rather a maximum removal of pollutant. That is accomplishedin part by using the most effective filter media available, of course,but also by providing as much filter medium as may be practical, whichrelates to the number, cross-sectional area, and depth of the filtersused.

The motor vehicle cabin also presents a particularly difficult problemin reducing air pollution, since the vehicle cabin is not a closedsystem, but “new” air is continually being drawn into it through thevehicle ventilation system. Ventilation systems that have a“recirculate” mode will tend to decrease the amount of such “new” airthat is being drawn in, of course, but there will still be some amountof “new” (and polluted) air being drawn in. It is thus only by acomparison of the air quality within the vehicle cabin at times that anair purifier is turned on, as compared to like data when no air purifieris operating, that any adequate measure of the performance of an airpurifier can be acquired. (This also suggests, of course, that to attainhigher purity air within a vehicle cabin, the ventilation systems shouldin fact be operated in that “recirculate” mode.)

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the complete air purifier (withoutupholstery), showing in outline the opening of the top thereof.

FIG. 2 is perspective view of the air purifier of FIG. 1 with the topclosed, and showing in cutaway an interior portion thereof thataccommodates the filter media packets.

FIG. 3 is another perspective, partially cutaway view of a differentlypartially assembled air purifier with the top closed, showing in thiscase the blower inside.

FIG. 4 is a longitudinal cross-sectional view in top plan of thecomplete air purifier, taken along the lines 4-4′ of FIG. 1, and showingthe blower, five filter media packets, and a HEPA filter.

FIG. 5 is a perspective, exploded view of the manner of construction ofa filter medium packet.

FIG. 6 is a longitudinal cross-sectional view in side elevation of theclosed air purifier, taken along the lines 6—6′ of FIG. 1.

FIG. 7 shows the complete air purifier, including upholstery, seat beltloops, and a flap over the clean air outlet, installed in the center ofthe rear (bench) seat of a motor vehicle.

FIG. 8 shows an alternative embodiment of the air purifier as installedin the trunk of an automobile, also showing the locations within thevehicle at which test instruments were located for conducting air puritytest measurements.

FIG. 9 shows in cutaway the interior construction of the console portionof the alternative embodiment of the air purifier of FIG. 8.

FIG. 10 is a bar graph representation of PM-10 air purity field testscarried out with the air purifier in Bangkok, Thailand, on Mar. 13,2000.

FIG. 11 is a bar graph representation of PM-2.5 testing in Bangkok,Thailand, on Mar. 13, 2000, using the same embodiment of the airpurifier as in FIG. 10.

FIG. 12 is a bar graph representation of PM-10 test results acquired inBangkok, Thailand, on Mar. 14, 2000, using a different embodiment of theair purifier from that of FIG. 11.

FIG. 13 is a bar graph representation of PM-2.5 test results fromBangkok, Thailand, on Mar. 14, 2000, using the same embodiment as thatof FIG. 12.

FIG. 14 is bar graph representation of a second set of PM-2.5 testresults, like those of FIG. 13, carried out in Bangkok, Thailand, onMar. 15, 2000.

FIG. 15 is a bar graph representation of PM-10 tests using theembodiment of FIG. 10, carried out in Los Angeles, Calif., on Aug. 2,1999, but wherein the air purifier was located in the vehicle trunk asshown in FIGS. 8-9.

FIG. 16 is a bar graph representation of PM-2.5 tests carried out in LosAngeles, Calif., on Aug. 3, 1999, where again the air purifier waslocated in the vehicle trunk.

FIG. 17 is a bar graph representation of analyses for nitrogen dioxide(NO₂) using a 211 CFM embodiment of the air purifier, on cabin airsamples taken Sep. 22-25, 2000, in Los Angeles, Calif., and Portland,Oreg., and later analyzed, and also showing the relevant healthstandard.

FIG. 18 is a bar graph representation of analyses taken and analyzedunder the same conditions as were the data in FIG. 17, except withrespect to sulfur dioxide (SO₂) and again showing the relevant healthstandard.

FIG. 19 shows data acquired as were those in FIGS. 17-18, but withrespect to lead (Pb) and again showing the relevant health standard.

FIG. 20 is a bar graph representation of data with respect to benzene,acquired in Los Angeles, Calif. on Sep. 1, 2000, by Summa canistersampling.

FIGS. 21-26 show analytical results from the samples of FIG. 20,analyzed at the same time and in the same manner, but as to thehydrocarbons toluene, ethylbenzene, and p-xylenes, o-xylene,1,3-butadiene, and t-butylmethyl ether, respectively.

FIG. 27 is a summary concentration chart of test results in the citiesof Portland, Oreg., Los Angeles, Calif., and Bangkok, Thailand, usingthe detector locations shown in FIG. 8, as these results are indicatedin FIGS. 10-26, and further indicating the related government healthstandards (in bold).

FIG. 28 incorporates footnotes to FIG. 27, indicating the times andplaces of the respective measurements or sampling, the particularinstrument or sampling method used, and, where applicable, specifyingthe independent and certified laboratory that carried out a subsequentanalysis and the method used.

BEST MODES OF CARRYING OUT THE INVENTION

FIG. 1 shows the overall construction of air purifier 10, which is aself-contained unit in the sense that an air inlet, an array of filters,a blower and an air outlet are all contained therein, the onlyadditional relationships to the motor vehicle itself being (a) means forremovably attaching air purifier 10 to a selected surface within themotor vehicle; and (b) for operational purposes, connection of airpurifier 10 to a power source derived from the motor vehicle. Ifemployed in a stable environment other than a motor vehicle or a boat orthe like (e.g., a hospital room), actual attachment of air purifier 10to the location site may not be necessary.

Further in FIG. 1, the indicated housing 12, which conveniently may bein the shape of an elongate rectangular box, can be fabricated fromlightweight aluminum plate by cutting, bending and riveting into thedesired shape, or as an alternative from molded plastic. Housing 12 isseen to comprise a grated front plate 14 into which cabin air is to bedrawn as shown by arrow 16; a bottom plate 18; two side plates 20 (ofwhich only one is shown in FIG. 1); a rear plate 22; and a top plate 24.Bottom plate 18, side plates 20 and rear plate 22 are cut and bent asindicated above and then riveted or otherwise connected together intothe disposition shown in FIG. 1, while top plate 24 is attached to thetop edge of rear plate 22 with a hinge 26 as shown in FIG. 1 in cutaway.By the use of hinge 26, top plate 24 can be raised into an “open”position as shown in outline in FIG. 1 so as to provide access intohousing 12 for initial assembly, and also for the installation andremoval of filter media packets as will be discussed below.

In one embodiment of this aspect of the invention, front plate 14, whichfor example may be 8″×10″ (20.32 cm×25.4 cm) in dimension, may contain48 one-inch square rectangular holes 28 in a 6×8 array, or alternativelyfront plate 14 may have different dimensions and contain 40 holes 28 ina 5×8 array as shown in FIG. 2, such holes 28 in either case preferablyhaving been stamped out of a flat aluminum plate, and serving to allowcabin air to enter housing 12 as noted above. In either such embodiment,however, or in any other disposition of holes 28, it is essential thatfront plate 14 and the filters to be discussed below have the samenumber of holes, in the same geometry, and that such holes be placed inalignment in passing from front plate 14 through those filters as willbe described hereinafter.

Top plate 24 has two mutually parallel transverse bends 30 a, 30 btherein, and the two sides 20 have vertical extensions 32 (of which onlyone is shown in FIG. 1) that are dimensionally matched to the bottomprofile of top plate 24. Vertical extensions 32 are intended to comeinto air-tight juxtaposition with top plate 24 when the same is in a“closed” disposition. Bends 30 and vertical extensions 32 serve toenlarge the vertical dimension of housing 12 in the rearward portionthereof so as to yield an elevated portion 34 under which can beaccommodated a blower that exceeds the vertical dimension of housing 12in its frontward portion, but of course that form of construction actsonly to increase that vertical dimension would not be necessary were asmaller blower to be used.

Generally centrally located within elevated portion 34 is an air exithole 36, being preferably of about 8.9 cm (3.5″) in diameter, disposedwithin elevated portion 34 so as to allow purified air to flow out ofhousing 12 as indicated by outgoing air arrow 38. As shown in partialcutaway in FIG. 1, immediately beneath air exit hole 36 is a sieve plate40 that connects at opposite ends thereof by rivets or similar wellknown means to inner sides of opposite vertical extensions 32, sieveplate 40 including a sieve 42 that is placed into alignment with airexit hole 36 to prevent any objects from falling into air purifier 10.As is best seen in FIG. 3, blower mounting frame 44 is disposed beneathand coaxially with air exit hole 36, and has holes 46 passingtherethrough to permit mounting of blower 48 to sieve plate 40 by bolts50 or similar such means.

Also shown in FIGS. 1 and 2 is one of two belt holders 52, a second beltholder 52 (not shown) being disposed in a mutually facing relationshipon the opposite, non-visible (in FIGS. 1 and 2) side of housing 12. Beltholders 52 allow a seat belt (shown in FIG. 7) to be passed therethroughso as to hold air purifier 10 in a desired position on a vehicle seat,e.g., in the center of a rear bench seat of a motor vehicle. Such a“seat belt” is also installable at other locations within a vehicle as,for example, on the vehicle floor between two front seats, and in thatcase air purifier 10 could be installed between those two seats. FIG. 2shows air purifier 10 with top plate 24 in a “closed” position, togetherwith a cutaway portion depicting an air conduit 54 for installation ofthe filter media packets and the HEPA filter to be noted below.

Further shown in FIGS. 1-3 is a power inlet hole 56 through which passesa power cord 58 connecting within housing 12 to blower 48, there alsobeing a switch 60 disposed along power cord 58 exterior to housing 12,and finally a power plug 62 that inserts into a cigarette lighteraperture (not shown) of a motor vehicle so as to provide electricalpower to blower 48. Switch 60 may be a simple “on/off” switch, or maypreferably be a step switch that permits adjustment in the level ofelectrical power being provided to blower 48, and in such case blower 48would have a variable speed motor whereby the rate of operation of airpurifier 10 could be adjusted as desired. For safety purposes, anyresistors used to divide or adjust the power should be located withinhousing 12 rather than in switch 60. Power cord 58 can preferably be2.44 m (8 feet) long, and in a preferred embodiment power cord 58 wouldbe connected to a three position switch 60, with an extension ofapproximately 25.4 cm (10 inches) thereof from switch 60 to power plug62, which preferably contains a 10-amp fuse.

Also shown in FIG. 2 within air conduit 54 is one instance of a filterframework 64, which as shown is simply two grates that in the embodimentfrom which the experimental data to be shown below were taken had thesame construction as front plate 14. As will be shown in FIG. 5,however, a newer embodiment is now known to be more preferred, in whichthe two grates differ in construction, but in any case between suchgrates there is to be placed a particular filter medium packet as willbe described below. Filter framework 64 is shown here with no filtermedium packet therewithin simply to show the construction of the gratesinitially used, and also to illustrate the positioning of the filtermedia packets within pre-determined filter locations as will bediscussed below.

Further provided within air conduit 54 is an array of separator plates66, in the space between which (that space comprising a “filterlocation,” including slots) are to be placed additional filter mediapackets, in a like manner, separator plates 66 being attached to facinginner surfaces of side plates 20 in a mutually facing manner by rivetingor similar well known means. The indicated space between separatorplates 66 is termed a “filter location.” In FIGS. 2, 3 are also shownscrews 68 that can be tightened down to hold a front edge of top plate24 firmly onto front plate 14 so as to attain air tightness after theHEPA filter and filter media packets have been installed, and top plate24 has been placed in its “closed” position, thus to permit normaloperation of air purifier 10.

FIG. 4, which is a longitudinal cross-sectional top plan view of airpurifier 10 taken along the lines 4-4′ of FIG. 1, shows within airconduit 54 the preferred arrangement of individual filters and filtermedia packets, i.e., dessicant-sorbent packet 70, carbon particle packet72, catalyst packet 74, coconut based carbon packet 76, HEPA filter 78,and impregnated carbon filter 80 (also coconut based), which is placedimmediately adjacent the exit side of HEPA filter 78. HEPA filter 78 isfactory made, while filter media packets 70-76 and carbon impregnatedfilter 80 were hand assembled.

As shown in FIG. 5, the preferred assembly of each filter media packet,which may but need not have a rectangular structure, may include the useof first and second 20.3 cm×25.4 cm (8″×10″) grates 82, 84, whichpreferably may be formed from aluminum sheet and are used similarly tothe manner previously shown to comprise filter framework 64 in FIG. 2.Grates 82, 84, which respectively include first holes 28 a and secondholes 28 b which have a size and location to form a mutually facingrelationship with holes 28 of front plate 14, are to be disposed withinselected filter locations between 1 cm (⅜″) separator plates 66,separator plates 66 being disposed along inner surfaces of walls 20within air conduit 54 as shown in FIGS. 2, 4. Filtering means will beplaced between each pair of grates 82, 84, which filtering means willinclude a sealed filter medium envelope 86, preferably of a non-woven,filter material that will at least remove gross, if not fine,particulate matter, and preferably having a weight about 70 gm/m², thematerial used in the embodiments with which the tests to be describedbelow were carried out having been a material produced by Technostat,although other types and sources of materials of which filter mediumenvelope 86 is formed, and that might be substituted for that justdescribed, will be known to a person of ordinary skill in the art, andany such substitutions would be deemed to fall within the spirit andscope of the invention. Each of filter medium envelopes 86 will befilled with close to 0.53 liter (2.25 cups) of a granular or pelletizedfilter medium 88 (the term “carbon particle” being used to encompasseither form) selected from the several types that were shown above tocharacterize filter medium packets 70-76, said filter medium 88 beingshown in cutaway in FIG. 5, and the filter medium envelope 86 so filledwill be placed between grates 82, 84 as is also shown in the explodedview of FIG. 5. The combination of grates 82, 84 and a filter mediumenvelope 86 containing filter medium 88 is termed a “filter structure.”

In assembling each filter media packet, each filter medium envelope isvibrated and compacted to ensure that a full and even amount of granularor pelletized material is contained between each grate from top tobottom and side to side. Also, the quantity of filter medium used, andhence the thickness of a filled filter medium envelope 86, is such as tocause those portions of filter medium envelope 86 that are adjacent toholes 28 a, 28 b to bulge outwardly therefrom, and as shown in FIG. 5,the relative amounts of those bulges will give a visual indication thatthe filter medium has in fact been distributed evenly and tightlythroughout the filter medium packet. This is critical to the properfunctioning of these filter media packets so that vibration of airpurifier 10 when in use in a moving vehicle cannot disturb filter medium88 so as to create voids through which air that would not be filteredcould pass. It is also elemental to the concept of the filter mediumpacket that as much medium surface be exposed to the air passingtherethrough as is possible, hence it is important that as much mediumbe used as the envelope into which the medium is packed willaccommodate.

The filter media packets that were used in the course of gathering theexperimental data indicated below were hand filled, i.e., a filtermedium envelope 86 filled with filter medium 88 was inserted between thetwo grates, and the two grates were squeezed together by hand and thenbound by tape. (Filter medium envelope 86, filter medium 88 and grates82, 84 as fully assembled in the manner just described, or also asdescribed below, constitute a “filter media packet,” the plural “media”being used since both filter medium envelope 86 and filter medium 88constitute filter media in the generic sense. A particular “filtermedium 88” may include a mixture of substances as was previouslyindicated, but nevertheless the singular term “medium” is used and isintended to refer to the content as a whole that is placed within filtermedium envelope 86.) Subsequent to the time at which those embodimentswere so hand made, and through use of which the experimental datareported herein were collected, it has been learned that holding the twogrates together can be better accomplished using the elongate U-shapedsliders 90. Sliders 90 are preferably formed of black molded rubber or asimilar such material, with sliders 90 further having a metal core, therubber or like material then coming into contact with separator plates66 when filter media packets 70-76 are placed therebetween as shown inFIG. 4, thereby to help ensure air-tightness so as to cause all incomingair to pass through each of the filter media packets. In lieu of thatconstruction of sliders 90, appropriately shaped gaskets may also beemployed.

In constructing a filter medium packet, as shown in FIG. 5, first filtergrate 82 is seen to be bounded on all four sides by walls 92. Filtermedium envelope 86 is placed within walls 92 (that space being termed a“filter medium container”), second filter grate 84 is placed atop filtermedium envelope 86 in contact with walls 92 and physically heldtogether, while sliders 90 are placed over the juncture between secondfilter grate 84 and walls 92 so as to hold first and second filtergrates 82, 84 together. Supplemental sliders 90 shown in phantom in FIG.5 may be added to the top and bottom of the resultant filter packet toaid further in providing airtight integrity of the filter packet withinair conduit 54. As will be known to a person of ordinary skill in theart, second filter grate 84 could instead be formed with walls in thesame manner as is first filter grate 82, the dimensions of such a gratebeing made either smaller than those of first grate 82, so that thewalls of this alternative grate fit tightly within walls 92, or larger,so that the exterior sides of walls 92 fit within the walls of thisalternative type of grate. (Of these two size alternatives, the latterwould be preferred in that this new type of grate could be placed aboutthe exterior of first filter grate 82 and its contained filter mediumenvelope 86 without disturbing the placement and tight packing of filtermedium envelope 86 that will already have been carried out within thefilter medium space of first filter grate 82.)

Another particular advantage of the indicated structure of the filtermedia packets is that no sealants or adhesives that might outgas VOC areused. Moreover, the filter media packets are recyclable in that most ofthe different filter media 88 can be removed and processed by heating orthe like to remove therefrom all sorbed pollutants and then returned touse, and grates 82, 84 and sliders 90 can also be reused.

The preferred construction of air purifier 10 comprises the specificsequencing of filter media packets as previously noted and shown in FIG.4. As best understood, when vehicle cabin air enters air purifier 10,dessicant-sorbent packet 70 acts to reduce the humidity of the incomingair and thereby to protect the effectiveness of carbon particle packet72 and catalyst packet 74. Desiccant-sorbent packet 70 preferablycontains 50% silica gel and 50% zeolite. The silica gel was obtainedfrom Silica Gel Desiccant Products Company and the zeolite was Zeochem®24-01, 4×8, type 4A. Carbon particle packet 72 may contain packed coalbased activated carbon pellets to adsorb ozone along with many othergases including sulfur oxides, the particular type of coal-based carbonused being pelletized type G352-60 made by the PICA company (France).Acidic gases such as sulfur oxides, which contaminate the air, may alsocontaminate the catalyst, so for effective operation of the catalystthose pollutants are preferably to be removed from the air before thatair reaches catalyst packet 74. The activated carbon so employed incarbon particle packet 72 may also contain impregnates to act aschemisorbents.

Catalyst packet 74 contains catalysts, specifically including a basemetal catalyst that is somewhat moisture tolerant and effective atambient air temperatures to break down carbon monoxide, and theCARULITE® 300 12×20 mesh catalyst made by the Carus Chemical Company wasused for this purpose because of its applicability to carbon monoxideoxidation. Coconut based carbon packet 76, which follows catalyst packet74, is intended to sorb benzene and other hydrocarbons, and containscoconut-based, activated carbon granules and/or beads necessary toadsorb the smaller hydrocarbon molecules, for which 50% PICA NacarP-20×50 and 50% PICA G55-C were used.

HEPA filter 78 was the HEPA PLEAT II®, a 6.35 cm (2.5″) deep pleated,high efficiency particulate filter, rated at 30.48 m/min (100 ft/min)and having an FPD (Filter Pressure Drop) of 0.53 W.G. (Water Gauge),mounted in an aluminum frame, which has been tested to remove 99.97% ofparticles measuring 0.3 microns in diameter, and being generally moreefficient for both the smaller and larger particles. Carbon impregnatedfilter 80 uses a carbon impregnated fiber (“CIF”), for which coconutcarbon wrap from Hepworth was used, and serves to capture residual gasesand odors. Carbon impregnated filter 80 is formed simply by looselyfolding the indicated fiber and taping the resultant folds of fibertogether, and is thus distinct in structure from the filter mediapackets previously discussed (and of course from the HEPA filter).

For purposes of completeness in the drawings, FIG. 6 is a longitudinalcross-sectional view in side elevation of closed air purifier 10, takenalong the lines 6-6′ of FIG. 1, and showing the manner of connection ofblower mounting frame 44 to sieve plate 40 using bolts/nuts 50 in aconventional manner. A gasket (not shown) can also be placed betweenblower mounting frame 44 and sieve plate 40 to help ensure air tightnessand reduce noise.

FIG. 7 shows air purifier 10 including an upholstered cover 94 asinstalled in a motor vehicle with power source 58-62 ready to beconnected to the vehicle cigarette lighter connector. Upholstery cover94 protects passengers from the hard metal edges of air purifier 10, andthe soft surface makes a comfortable console. Upholstery cover 94 isconstructed so as to cover firmly the top, back, two sides, and bottomof air purifier 10, and is secured in place using Velcro® strips (notshown). Cloth loops 96, of which only one is shown in FIG. 7, may besewn to each side of upholstery cover 94 in lieu of belt holder 52, as ameans to secure air purifier 10 to a vehicle seat with a seat belt. Asan alternative, upholstery cover 94 may be provided with slots in lieuof cloth loops 96, whereby belt holders 52 would pass therethrough to beused as noted earlier.

Also illustrated in FIG. 7 is an air exit flap 98, shown in solid whenair purifier 10 is not in use, and shown in outline when air purifier 10is in use such that air is exiting therefrom. Air exit flap 98 connectsto upholstery cover 94 to the frontward side of air purifier 10, so thatthe exiting air is directed upwardly and back towards the rear of thevehicle cabin, thereby not to impinge directly on the passengers.Through practice, it will be learned at what angle air exit flap 98should extend upwardly when air purifier 10 is working at its optimum,so that observation of a lower rising air exit flap 98 and thus a lesserflow of air would provide notice that such operation was not optimum,e.g., filter packets have become clogged or the like, and somemaintenance or replacement would be required. Air exit flap 98 alsoserves to lessen the noise detected in the vehicle cabin when airpurifier 10 is in operation.

FIG. 8 shows an alternative embodiment of air purifier 10 as installedin the trunk of an automobile, the figure for convenience also showingthe locations within the vehicle at which the test instruments werelocated for conducting the air purity measurements that will bediscussed below. In particular, FIG. 8 shows air purifier 10 installedwithin trunk region 100 of vehicle 102, such that air duct 104 connectsin an airtight fashion to air exit hole 36 of air purifier 10 by anyconvenient well known means. Air duct 104 undergoes such bends as arenecessary to bring it past a side of air purifier 10, towards the centerline thereof where another bend directs a terminal end of air duct 104forward into the rear seat area of the vehicle cabin, and having at thatterminal end of air duct 104 an air outlet 106 as best seen in FIG. 9.Air inlet extension 108 extends from the back seat region of vehicle 102downwardly into trunk region 100, whereby unpurified air can entertherein through air opening 110 as shown by incoming air arrow 112, andair inlet extension 108 is connected at its distal end in an airtightfashion to front panel 14 of air purifier 10 by any convenient means.

It can be seen in FIGS. 8, 9 that the particular embodiment beingdescribed has been adapted for use in those vehicle models that have agap in the back of the rear seat that leads into the trunk region, thatgap being provided to allow the carrying of long objects such as skiswithin the vehicle. For vehicles not so constructed, different routesfor incoming and outgoing air with respect to an air purifier 10 locatedwithin the trunk would need to be used, which might be done using an airinlet and outlet disposed beneath the rear seat of the vehicle andducted therefrom into the trunk region, an air inlet could be placedwithin the headliner of the vehicle and ducted therefrom to the trunk,or various other such configurations could easily be developed by aperson of ordinary skill in the art from the present disclosure, and allsuch variations are deemed to fall within the scope of the presentinvention It should be emphasized that all such ducting materials shouldbe of a type that does not itself “outgas” volatile organic compounds(VOC) and insert odorous chemicals into the air passing therethrough,that kind of outgassing often being found from ducts made of soft,flexible plastic-like materials disposed around a metal coil. For thatreason, an odor-free hard plastic material of the type often used forsewer pipe was used for the material of air duct 104, although there maybe other like materials that would serve as well, and these wouldlikewise fall within the scope of the invention.

FIG. 9 shows in cutaway the construction of that portion of the airpurifier 10 embodiment of FIG. 8 that is disposed within the rear seatarea of vehicle 102, wherein is also shown a console 114 formed of asemi-rigid plastic foam, within which is disposed a terminal portion ofair duct 104 leading to air outlet 106, and above which is disposed airopening 110. Preferably, console 114 will include a spongy cushion 116having a rounded surface, and preferably also side pouches 118 (of whichonly one is shown in FIG. 9) as well as cup holders 120 disposed atopconsole 114, perhaps attached by a Velcro® flap (not shown) or similarmeans, again for the convenience of the rear seat passengers.Preferably, console 114 will also have upholstery 122, as does theembodiment of air purifier 10 shown in FIG. 7, so that console 114 willmatch or blend in aesthetically with the vehicle cabin interior. (Ofcourse, the embodiment of air purifier 10 in FIG. 7 may similarly haveside pouches and cup holders.) Console 114 includes an air flap 124disposed over air outlet 106 for the same purposes as those of air exitflap 98. That is, air flap 124 serves to soften the noise, to indicateair flow strength, and is rotatably connected above air outlet 106 so asto direct the purified air downward.

Experimental Data

The experimental data that establish the performance of air purifierdevice 10 in its several prototype embodiments will now be shown anddescribed. In order to evaluate the utility and efficacy of the airpurifier in its several embodiments, available U.S. or foreign ambientair quality standards were identified as “targets” that it was hoped theair purifier would meet, a procedure that so far as Applicant knows hasnot been carried out in the previous art. As shown by the results below,the quality of the air tested as it exited air purifier 10 either met,or typically far exceeded, the relevant ambient air quality standards.These results seem to be particularly important with respect to the moretoxic and indeed lethal pollutants such as the toxic hydrocarbons(particularly benzene) and the “criteria” pollutant lead. All data werecollected inside a moving vehicle, passing through the crowded downtownstreets or freeways of the several cities cited, and, as indicated onthe several figures, data (or air) collection was carried out both withair purifier 10 turned off and turned on, and the lesser concentrationsof the various pollutants upon turning on air purifier 10 are shown.

All data except those for hydrocarbons were taken using a standard5-passenger sedan while carrying two or three persons; the aircollection procedures used for the hydrocarbon analyses were taken fromwithin a larger SUV while carrying four persons. In the course of usingeach such vehicle to gather the experimental data, the HVAC system ofthe vehicle itself was typically in full operation. These HVAC systemsare said to include what are variously termed “cabin air filters,”“pollen filters,” “micron filters,” or “air conditioning filters,” thesebeing advertised as means for capturing dust and pollen. However, thedata collected when air purifier 10 was not in use typically showedlevels of pollution, including that of fine particulate matter, oftenfar in excess of the relevant standards.

Before describing the actual experimental results, there is now given inmore detail the conditions under which air samples were either tested insitu or collected for later analysis, which types of instruments wereused, and which embodiment of air purifier 10 was used in what location.The several embodiments of air purifier 10 differ principally in thepower of blower 48, different ones of which were rated at 5 m³/min (176CFM), 6 m³/min (211 CFM), and 7 m³/min (250 CFM), and in each case whichblower was used in connection with each test or sample collection willbe noted. FIG. 8 shows the several positions A, B, and C within thecabin of vehicle 102 at which the sensing portion of particularinstruments were located in testing or collecting the air. All ofpositions A, B, and C center on the location of a seated passenger offto one side of air purifier 10 or console 114 and hence to one side ofthe air exiting therefrom, so that, presumably, the air being measuredwould have passed at least to the front of the cabin and then backagain, so as to get a better sampling of the cabin air as a whole thanwould have been accomplished with the test instrument in line with theair outlet of either air purifier 10 or console 114. The volume rate ofthe air exiting from air purifier 10 was not determined in all cases,but using the TSI VelociCheck™ anemometer and the cross-sectional areaof air outlet 86 at its terminus, it was determined that with a 7 m³/min(250 CFM) embodiment of air purifier 10 located in the vehicle trunk,the rate of air flow at outlet 106 was about 2.12 m³/min (75 CFM), basedupon a diameter of air outlet 86 of 3 inches (7.62 cm; area=45.6 cm²),and the measured air speed of 7.62 m/sec (1500 ft/min). From the ratiosof the area of air outlet 86 to that of front plate 14 (neglecting thespace therein not occupied by holes 28) of 20.32 cm×25.4 cm=516 cm², thespeed of the air entering into purifier 10 (i.e., V_(f)) can beapproximated at about 45.6/516 (1500 ft/min)=133 ft/min=0.67 m/sec.

Similar measurements of the air input speed on the 7 m³/min (250 CFM)embodiment as located in the trunk varied widely and were quitesensitive to the precise location of the anemometer sensor, valuesranging from 80 ft/min in the center of air opening 110 to around 400ft/min near the top thereof, which is reasonably consistent with thecalculated value just indicated. (Air inlet extension 108 extendsdownwardly to front plate 14 of air purifier 10 as disposed in thevehicle trunk, which could account for the air speed being higher nearthe top of air opening 110 (i.e., the opening to air inlet extension108) than near the center thereof.) The 6 m³/min (211 CFM) embodiment ofair purifier 10 as located on the vehicle rear seat was measured by theTSI VelociCheck™ anemometer to operate at an air input speed of about0.25 m/sec (50 ft/min).

Measurements of the air output speed of the 7 m³/min (250 CFM)embodiment located within the trunk, carried out on Feb. 6, 2001,indicated a speed of 6.1 m/sec (ft/min) on a “low” speed setting and 8.1m/sec (1600 ft/min) on a “high” speed setting. Measurements of the airoutput speed of the 6 m³/min (211 CFM) embodiment located on a vehiclerear seat, also carried out on Feb. 6, 2001, were more difficult in thatin this embodiment air exit hole 36 has a louver for “pointing” thedirection of the emerging air, and the measured air speeds variedsubstantially depending upon the precise location of the sensing probe.For the high speed operation, the measurements ranged from 1.0 m/sec(200 ft/min) to 7.6 m/sec (1500 ft/min), from which a composite andrather subjective average of 4.6 m/sec (900 ft/min) was estimated. Forthe low speed operation, the values ranged from 1.0 m/sec (200 ft/min)to 6.1 m/sec (1200 ft/min), yielding a similarly estimated average of3.8 m/sec (750 ft/min).

The descriptions of these tests that follow will identify the instrumentemployed for each particular measurement or collection, and at which ofthe three A, B, or C locations the test or collection was made. The term“PM-10” refers to particles 10 micrometers or less in diameter, and“PM-2.5” refers to particles 2.5 micrometers or less in diameter.

The instruments used were as follows:

1. Dräger CMS (Chip Measuring System) Gas Analyzer, wherein the relevant“chip” for each particular chemical species was employed.

2. Ozone Spot Checker.

3. MIE DataRAM™ Aerosol Monitor (portable and real time).

The analytical methods used, in the case of post sample-collectionanalysis, were:

1. EPA Method TO-14A. (Description of the method is available in PDFformat at the web sitehttp://www.epa.gov/ttn/amtic/files/ambient/airtox/to-14ar.pdf (visitedon Jan. 29, 2001).

2. NIOSH Method 6014. (Description of the method is available in PDFformat at the web site http://www.cdc.gov/niosh/pdfs/6014-1.pdf (visitedon Jan. 29, 2001).

3. OSHA Method ID-200. (Description of the method is available in HTMLformat at the web sitehttp://www.osha-slc.gov/dts/sltc/methods/inorganic/id200/id200.html(visited on Jan. 29, 2001).

4. OSHA Method ID-125. (Description of the method is available in HTMLformat at the web sitehttp://www.osha-slc.gov/dts/sltc/methods/inorganic/id125g/id125g.html orat http://www.osha-slc.gov/dts/sltc/methods/inorganic/id125g/id125g.pdfor in PDF format (visited on Jan. 29, 2001).

We shall now describe the manner of obtaining each of the experimentalresults, and in some cases their particular significance. These fieldresults are of course not “controlled,” in the strict laboratory sensethat comparisons could be made using different embodiments of airpurifier 10 under identical conditions, or similar such experimentalmodels—there was little if any control over the levels of pollution thatwould be encountered in driving through Bangkok, Thailand, Los Angeles,Calif., or Portland, Oreg., except that insofar as possible environmentsthat would be most challenging to air purifier 10 were sought out. Thedata obtained are not particularly clear also, in the sense thatsubstantial changes in the measured air particulate levels can be seento occur during periods when air purifier 10 was turned off (especiallynotable in FIGS. 13 and 14), hence it is not possible to attribute everydecrease in the pollutant level to the action of air purifier 10. Whatthese data do show that controlled laboratory tests cannot, however, isthat air purifier 10 is effective in providing “clean” air within avehicle cabin as it is being driven on the streets, i.e., cabin airhaving pollution levels as to the targeted pollutants that are below thestandards defined by the various government agencies. Of course thatgoal really is, or at least ought to be, the ultimate goal of the cabinair purification industry, and the data provided in the followingfigures show that it can be, and in fact has been, accomplished by thepresent invention.

FIG. 10 is a bar graph representation of PM-10 air purity field testsusing a 7 m³/min (250 CFM) embodiment of air purifier 10, as carried outin Bangkok, Thailand, on Mar. 13, 2000. The MIE DataRAM™ instrument wasused, positioned in the B position of FIG. 8, which roughly correspondsto a person sitting on one side of the rear seat of the vehicle andholding the instrument such that the actual air collection point thereonis positioned in front of the person at waist level.

FIG. 11 is a bar graph representation of the results of PM-2.5 testingin Bangkok, Thailand, on Mar. 13, 2000, again using the 7 m³/min (250CFM) embodiment referred to in FIG. 10. The MIE DataRAM™ test instrumentwas again used, positioned in the A position of FIG. 8, which roughlycorresponds to a person sitting to one side of the rear seat of thevehicle and holding the instrument such that the actual air collectionpoint thereon is positioned in front of the person at eye level.

FIG. 12 is a bar graph representation similar to that of FIGS. 10-11,now showing PM-10 test results acquired in Bangkok, Thailand, on Mar.14, 2000, but using a 5 m³/min (176 CFM) embodiment of the device. Thetest instrument used was again the MIE DataRAM™, positioned in the Aposition of FIG. 8.

It may be noted that the PM-10 values shown in FIGS. 10 and 12 weretaken under comparable conditions, i.e., in Bangkok, Thailand, aroundnoon time on successive days in mid-March, except that the data of FIG.10 were obtained using a 7 m³/min (250 CFM) embodiment of air purifier10 on Mar. 13, 2000, while those of FIG. 12 were obtained using a 5m³/min (176 CFM) embodiment on Mar. 14, 2000. As it happened, theambient air pollution levels (i.e., those measured with air purifier 10turned off) were quite a bit higher on Mar. 14, 2000, while using thelower powered embodiment, than those of Mar. 13, 2000, using the higherpowered embodiment. What is instructive from a comparison of these twodata graphs is that the lower powered embodiment, even when subjected toa rather greater challenge in terms of ambient air pollution, was fullyable to provide a very low level of cabin air pollution.

FIG. 13 is a bar graph representation similar to that of FIGS. 10-12,now showing PM-2.5 test results from Bangkok, Thailand, on Mar. 14,2000, again using a 5 m³/min (176 CFM) embodiment of the device. Thetest instrument used was again the MIE DataRAM™, positioned in the Cposition of FIG. 8, which roughly corresponds to a person sifting in thefront passenger seat of the vehicle and holding the instrument such thatthe actual air collection point thereon is positioned in front of theperson at waist level.

FIG. 14 is bar graph representation of a second set of PM-2.5 testresults using the same 5 m³/min (176 CFM) embodiment as referred to inFIG. 13, carried out in Bangkok, Thailand, on Mar. 15, 2000. The testinstrument used was the MIE DataRAM™, positioned in the C position ofFIG. 8.

FIG. 15 is a bar graph representation of PM-10 test results on the 7m³/min (250 CFM) embodiment of FIG. 10, carried out in Los Angeles,Calif., on Aug. 2, 1999, but wherein the air purifier device was locatedin the vehicle trunk as shown in FIGS. 8-9.

FIG. 16 is a bar graph representation of PM-2.5 test results using the 7m³/min (250 CFM) embodiment as referred to in FIG. 15, carried out inLos Angeles, Calif., on Aug. 3, 1999, where again the air purifierdevice was located in the vehicle trunk.

FIG. 17 is a bar graph representation of analyses for nitrogen dioxide(NO₂) using a 6 m³/min (211 CFM) embodiment of the air purifier device,on cabin air samples taken Sep. 22-25, 2000, in Los Angeles, Calif., andPortland, Oreg., as analyzed by Assay Technology Labs, Pleasanton,Calif., using Method NIOSH 6014, and also showing on the chart therelevant health standard. The air sample was collected using a glasstube, positioned in the B position of FIG. 8.

(The apparently equal values of these nitrogen dioxide concentrations,and likewise the sulfur dioxide concentrations of the following FIG. 18,are an artifact of the measurement process: those values were theminimum detectable values for the time period over which data wererecorded. It was estimated that in order to reduce that minimumdetectable value to a level at which distinctions between “purifier off”and “purifier on” could be drawn, it would have been necessary to drivethe streets steadily for some four hours, which for the comfort of theexperimenters would have been quite unbearable. These data are intendedonly to show that if the concentration in the air of the particularpollutant was not already below the health standard with the purifieroff, then that concentration could be reduced to below that level withthe purifier on.)

FIG. 18 is a bar graph representation of analyses taken and analyzedunder the same conditions as were the data in FIG. 17, except now withrespect to sulfur dioxide (SO₂) using Method OSHA ID 200, and againshowing the relevant health standard. The air sample was again collectedusing a glass tube positioned in the B position of FIG. 8.

FIG. 19 shows data acquired as were those in FIGS. 17-18, but withrespect to lead (Pb) using Method OSHA ID 125 and again showing therelevant health standard.

FIG. 20 is a bar graph representation of data with respect to benzene,acquired in Los Angeles, Calif. on Sep. 1, 2000 and later analyzed byPerformance Analytical, Inc., Simi Valley, Calif., using EPA MethodTO-14A. The air sample was collected using a Summa canister positionedin the C position of FIG. 8.

FIGS. 21-26 show analytical results from the samples of FIG. 20,analyzed at the same time and in the same manner as were those withrespect to FIG. 20, but as to the aromatic hydrocarbons toluene,ethylbenzene,—and p-xylenes, and o-xylene; aliphatic 1,3-butadiene, andfinally t-butylmethyl ether, respectively.

FIG. 27 is a summary concentration chart of test results in the citiesof Portland, Oreg., Los Angeles, Calif., and Bangkok, Thailand, usingthe detector locations shown in FIG. 8, as these results are indicatedin FIGS. 10-26. The major pollutants targeted by this invention areindicated, together with the relevant government health standards (inbold), pollutant levels found inside moving cars in nine separatescientific studies (of which one was the present study as to datacollected when air purifier 10 was not in use), and finally the levelsfound when air purifier 10 was turned on. It may be noted that wherepossible, the more stringent of available ambient air standards was usedas the “target.”

FIG. 28 comprises footnotes that pertain to the material of FIG. 27.More specifically, these footnotes show the dates of data collection andtypes of testing that resulted in the mean concentration numbers shownin the right hand column of FIG. 27, those data indicating the typicalperformance of air purifier 10 for each pollutant tested.

Industrial Applicability

From these data, it is evident that air purifier 10 achieves levels ofair purification not previously reported. A part of that success derivesfrom identifying specific pollutant levels as indicated in governmentstandards as “targets” for which lower pollutant levels are to beachieved. The means by which those lower levels were achieved center onthe decision, contrary to the industry practice, to concentrate onimproving environmental conditions for vehicle cabin inhabitants forhealth reasons rather than just minimal customer satisfaction.

Placement of the air purifier outside of the vehicle ventilation system,likewise contrary to industry practice, was one means by which that goalwas achieved, and centers on (a) the constructive use of cabin space forplacement of air purifier 10 or console 114; (b) the development of anaesthetically pleasing and useful structure for each of thoseplacements; (c) and a compactness in the structure of air purifier 10 soas to allow both of those features. This placement avoids one problem inthe prior art, namely, the safety of the passengers with respect todevices that have been installed in the cabin head liner, giving thedanger of bumping the head, and any kind of placement on the vehiclefloor (except between seats, or elsewhere in larger SUVs where suchplacement can be accommodated), where the device may be bumped into ortripped over. Given that various types of trays or holders for coins,cups, audio tapes or CDs and the like have now become common in thecabin areas of automobiles, and have been placed in both the front andrear seat areas of such vehicles, either one of air purifier 10 orconsole 114 would be expected to have similar customer acceptance andapproval, while at the same time, and most importantly, either of thosewould also be purifying the cabin air, that function within a consolenot being present in the prior art.

Another aspect lies in the innovation wherein the filter media packetswere structured as a quantity of filter medium enclosed within a filtermedium envelope that was itself formed from a non-woven, at least grossparticulate filter material. Standard industry practice, in packaging upa quantity of filter medium, has been simply to use a “scrim” materialthat does not itself contribute any filtration function. At least someat least gross particulate filtering thus occurs at each of the filtermedia packets, contributing to better use of the HEPA filter for itsbest purpose, namely, the capture of fine PM_(2.5) particles thatordinary filters cannot capture. It has also been shown that yet anothertype of air filter can be formed simply by folding up a quantity ofcarbon impregnated fiber.

Yet another aspect of the invention lies in the use of a packed bedfilter structure, which to the knowledge of this inventor has not beenused before in the cabin air filtration industry, for the apparentreason that the emphasis on maintaining a high velocity of air flow,given that the filtering device was to be placed within the vehicle HVACsystem, would preclude any use of packed bed filters. It was thus quiteunexpected that effective air purification could in fact be accomplishedby passing air through not only a total of 3 inches (i.e., four filtermedia packets each of ¾ inch depth) of tightly packed filter media, butalso through eight layers of the at least gross particulate mediumforming the envelopes surrounding those packed beds, through a HEPAfilter, and finally through a carbon impregnated fiber filter, but thedata set out herein show that result.

Another unexpected result of this experimentation, as determined fromvaried usage of the several embodiments of the invention, lies in thelong life of air purifier 10. For example, the input air speeds of the 7m³/min (250 CFM) embodiment located within the trunk carried out on Feb.6, 2001, which embodiment contains the filter media packets and otherfilters used in the tests reported herein, indicated speeds of 6.1 m/sec(1200 ft/min) on a “low” speed setting and 8.1 m/sec (1600 ft/min) on a“high” speed setting, thus showing no detectable degradation inperformance. The mileage records for the vehicle in which thatembodiment has been installed (excluding the Bangkok, Thailand tests forwhich a rented vehicle was used) indicate such usage over slightly morethan 2 years, and a mileage during that period of 30,560 miles.

The utility of employing a “low” and a “high” level operation of airpurifier 10 by way of switch 60 was also demonstrated. In usage, it wasfound that once the desired pollution level within the vehicle cabin hadbeen achieved (through use of either level), it was possible to maintainthat level (i.e. the particulate level was in single digits) overseveral hours by operating at the low level. Upon chance encounter of asubstantial pollution source (e.g., a diesel truck), the pollution levelwould be seen to rise, but could be reduced again by switching to thehigh level for a short period.

In employing air purifier 10 to eliminate airborne infectious agents,the contraction of some new disease while in a hospital is well known.With tuberculosis, for example it has become the practice of somehospitals to provide for such patients rooms that have “negativepressure,” which is to say that none of the air of that room is allowedto escape therefrom, a pressure differential being provided between thatroom and the hallways or the like for that purpose. For use in ahospital environment, it would fall within the scope of the invention toprovide air purifier 10 with filters especially adapted to capture thoseand other infectious agents, and also filters more closely adapted tocapture “hospital smells,” e.g., formaldehyde and methyl alcohol.Hospitals, and also nursing homes, often have air filtration systemsthat, like many of those installed within the ventilation systems ofmotor vehicles, are directed primarily to the removal of particulatematter and odors, not necessarily including the pollutants that in factpresent the greatest health risk.

With respect to the air in the cabins of aircraft, such air at “takeoff”will usually include some quantity of the pollutants that arise from theoperation of aircraft engines, including both that from nearby aircraftand that from the particular aircraft itself, and the types ofpollutants deriving therefrom will be somewhat different from thosearising from roadway motor vehicles, and again other types of filtersmay be provided to an air purifier 10 that would target those particularpollutants. Other types of environment that present their own uniquedistribution of pollutants are found in mobile homes, RVs (RecreationalVehicles), manufactured homes, houseboats, yachts, and the like. Withrespect to motor vehicles having separate cabin and cargo spaces, theembodiment described above which places air purifier 10 within thevehicle trunk may be taken to be exemplary of other such applicationswherein air purifier 10 is placed within the cargo space and issimilarly connected through air ducts to the cabin. Such application maybe particularly desired (in the case of cargo trucks adapted to receivethe installation of such air ducts) when the truck is routinely used tocarry odoriferous cargo such as livestock, farm produce, or garbage, theodors of which the user of the truck would like to avoid insofar aspossible.

The invention having thus been shown and described, it will beunderstood by those of ordinary skill in the art that other arrangementsand disposition of the several aforesaid components, the descriptions ofwhich are intended to be illustrative only and not limiting, may be madewithout departing from the spirit and scope of the invention. Each ofthese applications of the invention, as adapted by the means describedherein to best meet the needs of each of those specific environments,would be deemed to be encompassed by the invention. Therefore, thespirit and scope of the invention must be identified and determined onlyfrom the following claims and equivalents thereof.

I claim:
 1. An air purifier for the reduction of specific air pollutantswithin motor vehicle cabins and similar enclosed structures comprising:a portable housing having an air inlet in communication with the cabinof a vehicle and similar enclosed structures, a filter assembly incommunication with the air inlet and air outlet and selected filtermedia to remove specific pollutants from air flowing through the filterassembly, an air outlet in communication with the cabin of a vehicle, amotorized fan operable to draw air into the air inlet, through thefilter assembly and through the air outlet; the motorized fan operablefrom a readily accessible power source; the air purifier functionallyindependent of but also operable in conjunction with any heating,ventilation or air conditioning system in a motor vehicle and othersimilar apparatus; the housing removably attachable to at least onepreselected surface within or on a motor vehicle or other enclosedstructure; and the air purifier adapted to accept for purification onlythat air which is contained within said cabin or similar enclosedstructure, to the exclusion of immediate connection to air entering saidcabin or similar enclosed structure from areas external thereto.
 2. Theair purifier of claim 1 further comprising at least one packed bedfilter through which ambient air to be purified is passed.
 3. The airpurifier of claim 1 further comprising at least one HEPA filter throughwhich ambient air to be purified is passed.
 4. The air purifier of claim1 further being a self-contained unit.
 5. The air purifier of claim 1further comprising air inlet and air outlet apertures least one of whichis attached an air conduit extension.
 6. The air purifier of claim 1further comprising at least one of said filter locations adapted toreceive a HEPA filter.
 7. The air purifier of claim 6 includes a bloweremploying an electric motor that is operable from DC electrical power ofa motor vehicle, or AC electrical power from a similar enclosedstructure, and such power means includes a power cord attachable to apower outlet.
 8. The air purifier of claim 7 further comprising said DCelectric motor being operable at a plurality of speeds.
 9. The airpurifier of claim 6 being disposed within a trunk region of a motorvehicle, and wherein said air inlet and air outlet hole have fluidconnection to a cabin area of said motor vehicle.
 10. The air purifierof claim 9 wherein said air outlet hole connects to an air outletdisposed within an armrest/console, which is disposed on a rear seat ofa motor vehicle.
 11. The air purifier of claim 6 wherein at least one ofsaid at least one filter media packet includes a packed bed of filtermedium.
 12. The air purifier of claim 6 wherein at least one filtermedia packet comprises: a first grate; a second grate; and at least onefilter medium disposed between said first grate and said second grate.13. The air purifier of claim 12 wherein at least one of said at leastone filter media packet includes a filter medium envelope within whichis disposed said at least one filter medium.
 14. The air purifier ofclaim 13 wherein said filter medium envelope is formed of a non-woven,at least gross, as opposed to fine, particulate filter material.
 15. Theair purifier of claim 6 wherein at least one filter media packet isselected from the group consisting of a desiccant-sorbent packet, acarbon particle packet, a catalyst packet, and a coconut based packet.16. The air purifier in claim 15 wherein at least one filter mediapacket, commencing from said air inlet, are disposed in the order of: adesiccant-sorbent packet; a carbon particle packet; a catalyst packet;and a coconut based carbon packet.
 17. The air purifier of claim 16further includes at least one HEPA filter downstream of said filtermedia packets.
 18. The air purifier of claim 17, further includes atleast one impregnated carbon fiber filter downstream of said HEPAfilter.
 19. The air purifier of claim 1 further comprising said housingor cover having a seat belt bracket for connection to a motor vehicleseat belt.
 20. The air purifier of claim 1 including said housing orcover having a seat belt bracket for connection to a motor vehicle seatbelt.
 21. The air purifier of claim 1 further includes said blowerhaving a DC electric motor that is operable from DC electrical power ofa motor vehicle, and said power means includes a power cord that isattachable to a DC power outlet in a motor vehicle; or having an ACelectric motor that is operable from AC electric power available insimilar enclosed structures.
 22. The air purifier of claim 21 furthercomprising said DC electric motor being operable at a plurality ofspeeds.
 23. The air purifier of claim 1 further comprising said housingbeing disposed within a trunk region of a motor vehicle, and whereinsaid air inlet and air outlet hole are in fluid connection to a cabinarea of said motor vehicle.
 24. The air purifier of claim 23 furthercomprising an air outlet in communication with said air outlet hole andis disposed within an armrest/console disposed on a rear seat of a motorvehicle.
 25. The air purifier of claim 1 wherein at least one of said atleast one filter media packet includes a packed bed of filter medium.26. The air purifier of claim 1 wherein at least one of said at leastone filter media packet comprises: a first grate; a second grate; and atleast one filter medium disposed between said first grate and saidsecond grate.
 27. The air purifier of claim 26 wherein at least one ofsaid at least one filter media packet includes a filter medium envelopewithin which is disposed said at least one filter medium.
 28. The airpurifier of claim 27 wherein said filter medium envelope is formed of anon-woven, at least gross, as opposed to fine, particulate filtermaterial.
 29. An air purifier according to claim 1 wherein the specificair pollutants include but are not limited to: benzene, carbon monoxide,ozone, nitrogen dioxide, sulfur dioxide, lead, particles with diametersof 10 micrometers or less and particles with diameters of 2.5micrometers or less, which include but are not limited to: lead,cadmium, mercury, asbestos, disease-causing bacteria, viruses and fungi,carcinogenic volatile organic compounds that are attached to the saidparticles, sulfates, nitrates and diesel particulate soot.
 30. A methodof reducing specific pollutants from air within a motor vehicle cabin orsimilar enclosed structure, comprising the steps of: removably attachingan air purifier that is operable by power onto a surface within saidcabin or similar enclosed structure; said air purifier including an airinlet and an air outlet, both of said air inlet and air outlet being indirect fluid connection with the interior of said motor vehicle cabin orsimilar enclosed structure while having no direct fluid connection toany HVAC or other ventilation system that enters into said motor vehiclecabin or similar enclosed structure from the exterior thereof;connecting to said air purifier a proximal end of a power line adaptedto transmit DC power; and connecting a distal end of said power line toa source of power that is accessible from within said cabin or similarenclosed structure.
 31. An air purifier for the reduction of specificpollutants from the cabin of a vehicle and similar enclosed structures,comprising: a housing including an air conduit extending through saidhousing, said housing having on at least part of the exterior thereof anupholstery cover or other cushioning substance; an air inlet in fluidconnection with a first end of said air conduit; an air outlet hole influid connection with a second end of said air conduit; a multiplicityof filter locations disposed within said air conduit, at least one ofsaid filter locations being adapted to receive a filter media packetwithin said air conduit; at least one filter media packet disposedwithin one of said multiplicity of filter locations and selected tocapture at least one predetermined air pollutant from air passingthrough said air conduit; a blower in fluid connection with said airconduit and adapted to draw air into said air conduit through said airinlet and discharge air out of said air conduit through said air outlethole; and a connector for connecting to a power source for operatingsaid blower.
 32. The air purifier of claim 31 wherein said at least onefilter media packet is selected from the group consisting of adesiccant-sorbent packet, a carbon particle packet, a catalyst packet,and a coconut based carbon packet.
 33. The air purifier of claim 32wherein said at least one filter media packet, commencing from said airinlet, are disposed in the order of: a dessicant-sorbent packet; acarbon particle packet; a catalyst packet; and a coconut based carbonpacket.
 34. The air purifier of claim 33 further comprising a HEPAfilter downstream of the plurality of filter media packets.
 35. The airpurifier of claim 34 further comprising at least one carbon impregnatedfiber filter downstream of said HEPA filter.
 36. An air purifieraccording to claim 31 wherein the specific air pollutants include, butare not limited to: benzene, carbon monoxide, ozone, nitrogen dioxide,sulfur dioxide, lead, particles with diameters of 10 micrometers or lessand particles with diameters of 2.5 micrometers or less, which particlesinclude, but are not limited to: lead, cadmium, mercury, asbestos,disease-causing bacteria, viruses and fungi, toxic volatile organiccompounds that are attached to the said particles, sulfates, nitratesand diesel particulate soot.
 37. An air purifier operable to reduceconcentration levels of specific pollutants in the passenger cabin of avehicle and similar enclosed structures, to levels at least as low asthe following US-EPA National Ambient Air Quality Standards for at leastone of the following: Carbon Monoxide-20 parts per million, Ozone-80parts per billion, Nitrogen Dioxide-250 parts per billion, SulfurDioxide-636 parts per billion, Lead-1.5 micrograms per cubic meter,Particulate Matter 10 micrometers and less in diameter-150 microgramsper cubic meter, Particulate Matter 2.5 micrometers and less indiameter-65 micrograms per cubic meter; and reducing Benzene to levelsat least as low as an ambient air quality standard in Europe of 10micrograms per cubic meter (or 3 parts per billion); the air purifiercomprising: a housing including and air inlet, and air outlet, a filterassembly disposed between the inlet and the outlet, and a blower fordrawing an air flow from the interior of the vehicle and similarenclosed structures into the air inlet, through the filter assembly andthrough the air outlet into the interior of the vehicle and similarenclosed structures.
 38. An air purifier according to claim 37 whereinthe Particulate Matter includes, but is not limited to: lead, cadmium,mercury, asbestos, disease-causing bacteria, viruses and fungi, toxicvolatile organic compounds that are attached to the said particles,sulfates, nitrates, and diesel particulate soot.